So today I let my brother take my civic for a ride since he needs to learn how to drive manual. Later, I drive the car and it seems as though it now pops out of 3rd gear, I dont even want to know how my brother was driving. Anyway, for at least 2 years now the car grinds mildly when I would shift it into 3rd, but now it just pops out. What could this mean? A friend recommended replacing the fluid, but I assume it's clutch, maybe both? The car has 130K miles and is a 00 civic ex, I pushed the car a little hard the first year I owned it so I can only assume it damaged the clutch a bit. I've babied it since then (which was 2 - 3 years ago) but I only assume this is clutch related..
what do you guys think

 

yea if it pops out its ur clutch either burnd out or jus has to chill for a bit same thing happn with my hatch a while back after my clutch got to hot didnt want to give me 1st or 3rd n was struggling bad in 2nd after 20mins i turnd my car back on n i struggled to get home but i got there after a day it drove jus fine again so i assume its your clutch to except he probably burned it out